Kinglet (nuclear primary)
Kinglet was a boosted fission primary used in several American thermonuclear weapons.
The W55 warhead for the UUM-44 SUBROC anti-submarine missile and the W58 warhead for Polaris A-3 were designed to use Kinglet, while the W47 warhead for Polaris A-1/A-2 were retrofitted with Kinglet to overcome the technical issues with the Robin primary the W47 was initially deployed with. Allegedly, only the W47Y2 was converted to the Mod 3 design using Kinglet.
Design
The Kinglet device was approximately in diameter, in length and weighed approximately.The device was of the two-point design. Two-point devices only require two detonators to fire the whole device, compared to earlier nuclear weapons that required tens of detonators.
Characteristics of the warheads that used Kinglet are:
| Warhead | Max Yield | Diameter | Length | Weight |
| W47Y2 Mod 3 | ||||
| W55 | ||||
| W58 |